In 24 ABY, Beviin was in the Bar Jaraniz on Nar Shaddaa when he was approached by a man named Udelen. Udelen sought to kill an opposition leader on Ter Abbes named Tholote B'Leph. According to Udelen, B'Leph was a bribe-taker who had an unnatural generosity in awarding government contracts when in power, and Udelen wanted him removed before the next month's elections. Udelen promised Beviin a hundred thousand credits. Uneasy about assassinating an opposition politico and the unrest it would cause on Ter Abbes, Beviin left the bar for his Gladiator assault fighter, Beroya, and contacted MandaloreBoba Fett. Fett told Beviin to take the contract, knowing Beviin was facing financial difficulties at the time. Beviin returned to the bar and accepted the deal. However, it is undetermined if Beviin carried out the contract.[1]

On Nar Shaddaa, Beviin met two Mandalorian females, a widow named Briika Jeban, and her daughter, Dinua, and Beviin decided to take care of the two. Briika and Dinua accompanied Beviin to a rendezvous with Udelen's forces. While Beviin and a group of other Mandalorians, including Boba Fett, waited for Udelen, they were ambushed by a type of fleet that had not been seen before. The strange ships were under the command of Udelen, who revealed himself as Nom Anor, a vanguard of the Yuuzhan Vong, an extragalactic species that intended to take control of the galaxy.[1]

The Yuuzhan Vong allowed Beviin and Fett to board the fleet's flagship for negotiations. Fett told Beviin to stay aware on the Yuuzhan Vong's organic ship, and take small pieces of the organic technology found there. While on board, Anor told Beviin and Fett that the Mandalorians had little choice but to assist the Yuuzhan Vong with their conquest of the galaxy. Anor promised good pay for the Mandalorians' help, and Fett accepted, with the condition that the Yuuzhan Vong would leave the Mandalore sector alone in the ensuing invasion.[1]

Anor then tasked the Mandalorians with securing a landing point for the Yuuzhan Vong on the Outer Rim world of Birgis. One week after the invasion of Helska IV by the Yuuzhan Vong, Beviin and the Mandalorians attacked Birgis' spaceport. As soon as the commandos landed, Fett made a large water tower near the spaceport explode, distracting the guards and personnel. From there, Beviin and the Mandalorians rushed into the main building of the spaceport, securing it for the Yuuzhan Vong ground invasion.[1]

After the Battle of New Holgha, Yuuzhan Vong subalternBur'lorr ordered Beviin and the Mandalorians to find a Jedi named Kubariet, who was still down on New Holgha, and take him alive. The Mandalorians found him without much trouble, beaten and battered on a rooftop. However, they disobeyed their orders, and, realizing that Mandalore had no future with the Yuuzhan Vong, allowed the Jedi to escape. A nearby Yuuzhan Vong warrior attacked Beviin after the Mandalorians disobeyed their orders. However, the Mandalorians attacked and killed the warrior, although Briika Jeban was killed in the battle, which officially ended their short-lived affiliation with the Yuuzhan Vong. Beviin adopted Dinua after her mother's death.[1]

Beviin fought in the Yuuzhan Vong War with Boba Fett, the Mandalorians, and Kubariet and was involved in the Battle of Mandalore where the Yuuzhan Vong were defeated, despite heavy casualties for the Mandalorian Protectors.[3]

After the Yuuzhan Vong War, Beviin settled down on Mandalore with his husband, Medrit Vasur, and their daughter, Dinua. By 40 ABY, he had become one of Boba Fett's most trusted lieutenants. In 40 ABY, Beviin was approached by Corellian politician Thrackan Sal-Solo, who offered him a contract to kill the whole Solo family. Beviin refused, stating that he did not kill families, just. He relayed this to Boba Fett on Taris, along with news about Fett's family; Fett's daughter, Ailyn Vel, was alive, working under the name Ailyn Habuur. Fett was not previously sure of his daughter's fate; she had hunted him for some time, angry about him leaving her and her mother, Sintas Vel, but had not encountered Fett for years.[2]

Later, Beviin was contacted by Boba Fett, who informed Beviin that Sal-Solo wanted the Mandalorians to help defend Centerpoint Station. Beviin was ordered to assemble as many commandos as he could and meet Fett in two days on Drall. After those two days passed, Beviin had been able to assemble half a dozen Mandalorians. During the Drall meeting, Beviin told Fett that he was a poor Mandalore, that after the devastation of the Yuuzhan Vong War, the Mandalorians needed more than just a figurehead. He told Fett of a man named Kad'ika, who Beviin believed to be a suitable Mandalore. After the assassination of Thrackan Sal-Solo, Beviin informed Fett of the death of Ailyn Vel.[2]

Later that year, Boba Fett left Mandalore for a few days, and appointed Beviin, his most trusted lieutenant, as acting Mandalore in his stead. During his short time in charge, Beviin mostly stayed home, shoveling dung and running his farm, which had not been doing well as of late. When Fett returned, he told Beviin one of his biggest secrets, revealing that he was terminally ill, and was not going to live much longer. At the same time, Beviin revealed that drillers had found a large load of beskar, Mandalorian iron, in the ground, and the newfound beskar could bring about a time of great economic growth for Mandalore.[5]

The ill Fett stayed at Beviin's farm for a while after this revelation, and, due to a DNA sample from Jaing Skirata, was a transfusion away from being healed. Beviin, along with Fett's granddaughter Mirta Gev and her fiancée Ghes Orade, visited Fett when he had his life-saving transfusion, and once Fett's surgery was done, Beviin showed him the Bes'uliik, a new starfighter made from the load of Mandalorian iron that had been recently found.[5]

In 40 ABY, the still-living body of Boba Fett's long-missing ex-wife Sintas Vel was found encased in carbonite. Beviin was present when DoctorBeluine released her from her carbonite prison and welcomed Vel as a guest at his farm, giving her a temporary home as she recovered from the amnesia, blindness, and other side effects of her years trapped in carbonite. When Jedi KnightJaina Solo came to Mandalore seeking Fett's training to kill her Sith Lord brother, Darth Caedus, Beviin greeted her at the Oyu'baattapcafe in the city of Keldabe. Beviin went on to become one of many Mandalorians to train Solo, also allowing the Jedi to stay at his farm while she was in training.[3]

Some time after Solo's arrival, Beviin took her to former Mandalore Fenn Shysa's memorial, and taught her some Mandalorian history. He then had a training duel with the Jedi, where Beviin flattened Solo. They fought several more times, with Beviin overwhelming her, forcing her to resort to using the Force. Beviin told Solo after these training bouts to be totally driven on finishing her opponent off, to be a different Jaina. Solo disagreed, believing that it was hate that Beviin was teaching her, but Beviin told her that it was not hate; it was total war. Even after Beviin reassured her of this, she still believed that his fighting style and lessons were of the dark side. Around this time Beviin also attended the wedding party of Mirta Gev and Ghes Orade.[3]

Beviin was known as something of a traditionalist, and used old-fashioned equipment, including highly illegal crushgaunts,[1] and beskar armor that was colored blue.[4] Beviin lived with his husband, Medrit Vasur, some time before 24 ABY.[1] The couple went on to adopt a daughter, Dinua Jeban. Beviin was a family man and was welcoming of guests on his farm.[2] Boba Fett thought of Beviin as all heart and courage, and not afraid of the pain of love.[3] He was the closest the anti-social Fett had to a friend.[2] Fett thought that Beviin would make a good Mandalore, but Beviin did not want to lead, and would rather stay on his farm.[5] Beviin held a deep hatred for the Yuuzhan Vong, and advocated killing every one. Beviin also held a dislike for the Jedi, and described Kubariet as "the only Jedi I've ever trusted."[3]

Though Beviin's husband, Medrit, had been mentioned in previous stories, it is not until Legacy of the Force: Sacrifice, by Karen Traviss, that he first appears as a character, and readers learn that he is a male Human.[5] This establishes the couple as one of the first openly homosexual couples in Star Wars literature. Although none of their appearances in canon specifically acknowledged Beviin and Vasur as married, by September2008 Karen Traviss had stated that they were.[8] Later, in December 2008, The Complete Star Wars Encyclopedia made their marriage explicit.[4]